Set tartufo in path of docker image

[connorjburton]

Feature Request

Is your feature request related to a problem? Please describe.

We are using tartufo in a multi stage docker build, there are two problems with this:

1. This approach isn't documented
2. tartufo isn't exposed on the path so you have to navigate to /var/venv to be able to run your scan, this alongside with point 1 makes it more difficult to setup that it should be.

Describe the solution you'd like

Document an example of how to use tartufo in multi stage builds

Expose tartufo onto the path so the example can be tartufo scan-local-repo

Describe alternatives you've considered

Documenting that you need to use /var/venv/tartufo

Teachability, Documentation, Adoption, Migration Strategy

As listed above, a lot of this is about documentation, so this should be paramount.

I am happy to do this work, I just need guidance on which option would be best.